In such gas blast switches, an AC current interruption is operated through two main successive stages, namely a pressurization stage and an arc extinction stage.
In the pressurization stage, as main contacts of the gas blast switch separate, electric current is carried through an arc between the male and female arcing contacts. The gas channel provides a path for feeding insulating gas heated by the arc, such as SF6 or alternatives to SF6, from the arcing region (a space enclosing a gap formed between the male and female arcing contacts) into the gas storage chamber, thereby inducing a pressure increase in the gas storage chamber.
Then, in the arc extinction stage, the direction of gas flow in the gas channel reverts and quenching gas, formed by high pressurized insulating gas previously stored in the gas storage chamber, flows into the arcing region through the gas channel. A blast of quenching gas thus cools the electric arc and enables the AC current to be interrupted.
A purpose of embodiments of the present invention is to improve the cooling performances of the quenching gas in such gas blast switch.